Sodium Thiosulfate
1 Nonproprietary Names SEM 1: Excipient: sodium thiosulfate; magnification: 100 ; voltage: 10 kV. BP: Sodium Thiosulphate JP: Sodium Thiosulfate Hydrate PhEur: Sodium Thiosulfate USP-NF: Sodium Thiosulfate
2 Synonyms Ametox; disodium thiosulfate; disodium thiosulfate pentahydrate; natrii thiosulfas; natrium thiosulfuricum; sodium hyposulfite; sodium subsulfite; Sodothiol; Sulfothiorine; thiosulfuric acid disodium salt.
3 Chemical Name and CAS Registry Number Sodium thiosulfate anhydrous [7772-98-7] Sodium thiosulfate pentahydrate [10102-17-7]
4 Empirical Formula and Molecular Weight
Na2S2O3 158.11 (for anhydrous) Na2S2O3 5H2O 248.2 (for pentahydrate) Table I: Pharmacopeial specifications for sodium thiosulfate. 5 Structural Formula Test JP XV PhEur 6.0 USP32–NF27 Identification þþþ Characters — þ — pH 6.0–8.0 6.0–8.4 — Appearance of solution þþ— Water — — 32.0–37% Calcium þ — þ Heavy metals 420 ppm 410 ppm 40.002% Arsenic 45 ppm — — Loss on drying þ —— 6 Functional Category Sulfides — þ — Sulfates and sulfites — 40.2% — Antioxidant. Assay (dried basis) 99.0–101.0% 99.0–101.0% 99.0–100.5%
7 Applications in Pharmaceutical Formulation or S Technology Sodium thiosulfate is used as an antioxidant in pharmaceuticals 11 Stability and Storage Conditions (ophthalmic, intravenous, and oral preparations). It has also been Sodium thiosulfate decomposes on heating. The bulk powder used for its antifungal properties(1) and as a reagent in analytical should be stored in a cool place, and the container should be kept chemistry. tightly closed in a dry and well-ventilated place. It should not be stored near acids. 8 Description 12 Incompatibilities Sodium thiosulfate occurs as odorless and colorless crystals, a crystalline powder or granules. It is efflorescent in dry air and Sodium thiosulfate is incompatible with iodine, with acids, and with lead, mercury, and silver salts. It may reduce the activity of some deliquescent in moist air. preservatives, including bronopol, phenylmercuric salts, and thimerosal.(1) 9 Pharmacopeial Specifications See Table I. 13 Method of Manufacture On an industrial scale, sodium thiosulfate is produced chiefly from 10 Typical Properties liquid waste products of sodium sulfide or sulfur dye manufacture. Small-scale synthesis is done by boiling an aqueous solution of Acidity/alkalinity Aqueous solution practically neutral at pH (2,3) 6.5–8.0 (pentahydrate). sodium sulfite with sulfur. Density 1.69 g/cm3 (pentahydrate) Hygroscopicity Slightly deliquesces in moist air (pentahydrate). 14 Safety Melting point 488C (pentahydrate) Sodium thiosulfate is used in ophthalmic, intravenous, and oral Solubility Soluble in water; practically insoluble in ethanol pharmaceutical preparations. Apart from osmotic disturbances, (95%). sodium thiosulfate is relatively nontoxic. It is moderately toxic by
671 672 Sorbic Acid
the subcutaneous route and mildly irritating to respiratory tract and The EINECS number for sodium thiosulfate is 231-867-5. The skin. Large oral doses have a cathartic action.(1) PubChem Compound ID (CID) for sodium thiosulfate pentahydrate (4) is 516922. LD50 (IP, mouse) 5.6 g/kg
LD50 (IV, mouse) 2.4 g/kg 19 Specific References 15 Handling Precautions 1 Sweetman SC, ed. Martindale: The Complete Drug Reference, 36th edn. London, UK: Pharmaceutical Press, 2009; 1466. Observe normal precautions appropriate to the circumstances and 2 Lowenheim FA, Moran MK, eds. Faith, Keyes & Clarks Industrial quantity of the material handled. Protective gloves are recom- Chemicals, 4th edn. New York: Wiley-Interscience, 1975; 769–773. mended for prolonged or repeated contact use. Hazardous products 3 Holleman AF, Wiberg E. Inorganic Chemistry. San Diego: Academic (sulfur oxides) are formed when heated to decomposition. Press, 2001; 1937. 4 Lewis RJ, ed. Sax’s Dangerous Properties of Industrial Materials, 11th 16 Regulatory Status edn. New York: Wiley, 2004; 3284–3285. 5 Frankenberg L, Sorbo B. Effect of cyanide antidotes on the metabolic GRAS listed. Included in the FDA Inactive Ingredients Database (IV ¨ conversion of cyanide to thiocyanate. Arch Toxicol 1975; 14: 81–89. solutions; ophthalmic solutions and suspensions; oral capsules, 6 Sylvester DM et al. Effects of thiosulfate on cyanide pharmacokinetics solutions, and tablets). Included in the Canadian List of Acceptable in dogs. Toxicol Appl Pharmacol 1983; 69: 265–271. Non-medicinal Ingredients. 7 Food Chemicals Codex, 6th edn. Bethesda, MD: United States Pharmacoepeia, 2008; 914. 17 Related Substances — 20 General References — 18 Comments Sodium thiosulfate has been used as an antidote to cyanide 21 Authors (5,6) poisoning. Thiosulfate acts as a sulfur donor for the conversion JC Hooton, N Sandler. of cyanide to thiocyanate (which can then be safely excreted in the urine), catalyzed by the enzyme rhodanase. There is a specification for sodium thiosulfate in the Food 22 Date of Revision Chemicals Codex (FCC).(7) 16 February 2009.
Sorbic Acid
1 Nonproprietary Names 6 Functional Category S BP: Sorbic Acid Antimicrobial preservative. PhEur: Sorbic Acid USP-NF: Sorbic Acid 7 Applications in Pharmaceutical Formulation or Technology (1) 2 Synonyms Sorbic acid is an antimicrobial preservative with antibacterial and antifungal properties used in pharmaceuticals, foods, enteral Acidum sorbicum; E200; (2-butenylidene) acetic acid; crotylidene preparations, and cosmetics. Generally, it is used at concentrations acetic acid; hexadienic acid; hexadienoic acid; 2,4-hexadienoic acid; of 0.05–0.2% in oral and topical pharmaceutical formulations, 1,3-pentadiene-1-carboxylic acid; 2-propenylacrylic acid; (E,E)- especially those containing nonionic surfactants. Sorbic acid is also sorbic acid; Sorbistat K. used with proteins, enzymes, gelatin, and vegetable gums.(2) It has been shown to be an effective preservative for promethazine 3 Chemical Name and CAS Registry Number hydrochloride solutions in a concentration of 1 g/L.(3) (E,E)-Hexa-2,4-dienoic acid [22500-92-1] Sorbic acid has limited stability and activity against bacteria and is thus frequently used in combination with other antimicrobial preservatives or glycols, when synergistic effects appear to occur; 4 Empirical Formula and Molecular Weight see Section 10. C6H8O2 112.13 8 Description 5 Structural Formula Sorbic acid is a tasteless, white to yellow-white crystalline powder with a faint characteristic odor.
9 Pharmacopeial Specifications See Table I.